Space Science Links for Teachers and Students:

Cosmology and CMB:

An Introduction to the CMB - https://background.uchicago.edu/%7ewhu/beginners/introduction.html
A tutorial on the physics of the CMB by Wayne Hu of the University of Chicago.
Cosmology Tutorial - https://www.astro.ucla.edu/%7ewright/cosmolog.htm
A college level tutorial on cosmology by WMAP Science Team member Ned Wright of UCLA.
Cambridge Cosmology - https://www.damtp.cam.ac.uk/research/gr
Brought to you by Cambridge University.
History of Cosmology - https://history.aip.org/exhibits/cosmology/index.htm
A site by the Center for History of Physics, a Division of the American Institute of Physics.

General astronomy:

Astronomy Picture of the Day - https://apod.nasa.gov/apod/astropix.html
Each day a different image or photograph of our universe is featured, along with a brief explanation written by a professional astronomer.

Educational sites of other NASA missions:

Chandra X-Ray Observatory - https://chandra.harvard.edu/edu/index.html
The NASA Great Observatory for studying the X-ray universe.
Hubble Space Telescope - https://hubblesite.org/
The NASA Great Observatory for studying the optical universe.
Spitzer Space Telescope (SIRTF Infrared Observatory) - https://www.spitzer.caltech.edu/
The NASA optical observatory for studying the infrared universe.
Other NASA Missions - https://www.nasa.gov/missions/
A complete linked list of past, present and future missions flown by the Office of Space Science at NASA Headquarters.
NASA Astrophysics Research - https://universe.gsfc.nasa.gov/
A List of current NASA projects studying Astrophysics.
NASA Science - https://science.nasa.gov
Information about NASA's science, education, and public outreach activities at NASA Science.

Educational Resources:

Astronomy Education at the AAS - https://aas.org/education
A portal to educational projects sponsored by the American Astronomical Society.
Astronomy Education at the ASP - https://astrosociety.org/education-outreach/
A portal to educational projects sponsored by the Astronomical Society of the Pacific.
CERES Project - https://btc.montana.edu/ceres/
An extensive collection of activities from Montana State University, many tied to NASA themes.
Google Earth- add on - https://earth.google.com
Download these KMZ files to view in Google Earth 4.2 or greater (Places menu) for a view of the Cosmic Microwave Sky.
Universe Forum - https://www.cfa.harvard.edu/seuforum/
2009 Archive of educational resources and ready made presentations on Cosmology- for teachers, scientists and informal educators.
NASA Quest - https://quest.arc.nasa.gov
Home of NASA's K-12 Internet Initiative for educational resources.
NASA Educational Services - https://www.nasa.gov/offices/education/about/index.html
Communicate with other teachers on the Web through this site.
The Known Universe- a movie - https://www.youtube.com/watch?v=17jymDn0W6U
American Museum of Natural History produced trip to the edge of the visible universe 6:31 min.
Astronomy Education Resources - https://astro.washington.edu/outreach
A K-12 Outreach Project at the University of Washington.
National Air and Space Museum - https://airandspace.si.edu//
The name says it all.
Careers in Astronomy - https://aas.org/careers/career-in-astronomy
An on-line pamphlet maintained by the American Astronomical Society.